1. Field of the Invention
The embodiments discussed herein relate to attenuator circuits provided on substrates (hereinafter “substrate attenuator circuits”). In particular, the embodiments are suitably applicable to attenuator circuits configured on substrates with thin, long conductive patterns having multiple bends.
2. Description of the Related Art
Conventionally provided attenuator circuits include one configured on a substrate with a resistive film having a thin, long conductive pattern bent at multiple portions (see, e.g., JP-A-05-021202). According to the technique described in JP-A-05-021202, an input terminal is provided at one end of the thin, long continuous conductive pattern, and output terminals are drawn out from a plurality of portions of the conductive pattern, such that desired resistance values are available therefrom.
FIG. 7 illustrates an exemplary configuration of the above-mentioned related art. In FIG. 7, a thin, long conductive pattern 101 of a uniform width is configured on a substrate 100 so as to have a folding pattern including multiple bends at an angle of 180 degrees. An input terminal 102 is provided at one end of the conductive pattern 101, and a plurality of output terminals 103A to 103C are drawn out from a plurality of portions of the conductive pattern 101.
Signals output from the first output terminal 103A are attenuated by a first resistance value corresponding to a conductive pattern portion 101A that is defined from the input terminal 102 to the first output terminal 103A. Signals output from the second output terminal 103B are attenuated by a second resistance value corresponding to the conductive pattern portion 101A and a conductive pattern portion 101B that are defined from the input terminal 102 to the second output terminal 103B. Signals output from the third output terminal 103C are attenuated by a third resistance value corresponding to the conductive pattern portions 101A and 101B and a conductive pattern portion 101C that are defined from the input terminal 102 to the third output terminal 103C. With this configuration, signals may be extracted from any of the output terminals 103A to 103C appropriately selected, and signals input to the input terminal 102 are thus attenuated for output by a desired level.
However, of the entire conductor area provided by the conductive pattern, the smaller the resistance value, i.e., the lower the attenuation level, to be attained by a conductive pattern portion defined from the input terminal to an output terminal, the smaller the conductor area to be used to provide that resistance value is. For this reason, a lower attenuation level entails increased power consumption per unit area, hence an increased amount of heat generation per unit area.